1. Technical Field
The present invention relates to a power supply apparatus for a vehicle which supplies electric power to a power supply unit and charges electric power from the power supply unit to a main battery of an electric vehicle, a plug-in hybrid vehicle or a vehicle with electrically driven auxiliary units via a power port.
2. Related Art
This type of power supply apparatus is disclosed in JP-A-2007-318970. This power supply apparatus uses an inverter which is operated to control power applied to drive wheels of a vehicle by a motor generator, thereby storing electric power supplied from an external commercial power source in a battery of the vehicle.
The above inverter is required to have high reliability. Generally, the operation of the inverter should be ensured for a required total period of time during which the vehicle can run. Meanwhile, a long time is generally required to store electric power supplied from an external commercial power source. Hence, when the required total period of time during which a vehicle can run is fixed, required durability of the inverter of a vehicle having a charging function can become excessive compared with that of a vehicle not having a charging function.
In addition, a battery in a vehicle is often connected to an auxiliary unit in addition to the inverter. The auxiliary unit is driven with high voltage by the battery. In this case, standby electric power can be consumed by a drive circuit and the like of the auxiliary unit when charging.